A mounting assembly is used to mount electronic modules, back-planes, shelves, circuit boards, or other electronic equipment in an enclosure. A mounting assembly sometimes compromises the environmental integrity of an enclosure, particularly where the mounting assembly engages a bore in the enclosure. The bore may provide a path for the ingress of water, dust, or other contaminants.
In the past, an elastomeric seal (e.g., silicone or rubber o-ring) was associated with the bore and the mounting assembly to weather-proof the enclosure. However, elastomeric seals used to seal such bores were susceptible to leakage and mechanical failure over time. For example, such elastomeric seals were damaged during installation when the mounting assembly required deformation to be secured to the bore.
If an exterior of the enclosure is exposed to rain, snow, ice or other sources of water, the water may penetrate the elastomeric seal. Upon exposure to the intruding water, the electronic modules within the enclosure may be damaged through one or more short-circuits created by conductive impurities (e.g., mineral salts) dispersed in the intruding water. In the context of an enclosure for wireless communications equipment, damage to an electronic module may lead to down-time of a wireless communications system or a portion thereof.
In general, an enclosure for housing communications equipment must meet various technical standards to be technically competitive and commercially marketable. For example, enclosures may be tested for salt-fog resistance and resistance to wind-driven rain at a certain rate over a certain duration and wind speed. One current technical standard involves rain testing as specified in paragraph 30 of the Underwriter's Laboratories specification UL 50 regarding "Enclosures for Electronic Equipment". Thus, the need exists for a mounting assembly and an enclosure that is sufficiently weather-tight to reduce or eliminate damage to electronic equipment housed in the enclosure.